U.S. patent application number 16/960131 was filed with the patent office on 2021-03-11 for machine for stabilizing a track.
This patent application is currently assigned to Plasser & Theurer Export von Bahnbaumaschinen GmbH. The applicant listed for this patent is Plasser & Theurer Export von Bahnbaumaschinen GmbH. Invention is credited to Nikolaus MATZINGER, Samuel WOLLANEK.
Application Number | 20210071369 16/960131 |
Document ID | / |
Family ID | 1000005275336 |
Filed Date | 2021-03-11 |
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United States Patent
Application |
20210071369 |
Kind Code |
A1 |
WOLLANEK; Samuel ; et
al. |
March 11, 2021 |
MACHINE FOR STABILIZING A TRACK
Abstract
The invention relates to a machine for stabilizing a track,
including a machine frame supported on on-track undercarriages and
a vertically adjustable stabilizing unit designed to roll on rails
of the track by means of unit rollers, the stabilizing unit
comprising a vibration exciter with rotating imbalance masses for
generating an impact force (F.sub.S) acting dynamically in a track
plane perpendicularly to a track longitudinal direction and a
vertical drive for generating a vertical load acting on the track.
In this, it is provided that the vibration exciter comprises at
least two imbalance masses which are driven applying a variably
adjustable phase shift (.DELTA..PHI..sub.1, .DELTA..PHI..sub.2).
The invention further relates to a method for operating such a
machine.
Inventors: |
WOLLANEK; Samuel;
(Pregarten, AT) ; MATZINGER; Nikolaus;
(Oberneukirchen, AT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Plasser & Theurer Export von Bahnbaumaschinen GmbH |
Vienna |
|
AT |
|
|
Assignee: |
Plasser & Theurer Export von
Bahnbaumaschinen GmbH
Vienna
AT
|
Family ID: |
1000005275336 |
Appl. No.: |
16/960131 |
Filed: |
January 14, 2019 |
PCT Filed: |
January 14, 2019 |
PCT NO: |
PCT/EP2019/050767 |
371 Date: |
July 6, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E01B 27/20 20130101;
E01B 2203/127 20130101 |
International
Class: |
E01B 27/20 20060101
E01B027/20 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 13, 2018 |
AT |
A 36/2018 |
Claims
1. A machine for stabilizing a track, including a machine frame
supported on on-track undercarriages and a vertically adjustable
stabilizing unit designed to roll on rails of the track by means of
unit rollers, the stabilizing unit comprising a vibration exciter
with rotating imbalance masses for generating an impact force
(F.sub.S) acting dynamically in a track plane perpendicularly to a
track longitudinal direction and a vertical drive for generating a
vertical load acting on the track, wherein the vibration exciter
comprises at least two imbalance masses which are driven applying a
variably adjustable phase shift (.DELTA..PHI..sub.1,
.DELTA..PHI..sub.2).
2. The machine according to claim 1, wherein a left-turning
imbalance mass and a right-turning imbalance mass form an imbalance
mass pair, and wherein at least one imbalance mass of said
imbalance mass pair is driven applying a first phase shift
(.DELTA..PHI..sub.1) which is variably adjustable with respect to
an initial position.
3. The machine according to claim 1, wherein an angle sensor is
associated with each imbalance mass.
4. The machine according to claim 1, wherein the respective
imbalance mass is arranged on the stabilizing unit with a rotation
axis being aligned in the track longitudinal direction.
5. The machine according to claim 1, wherein a separate drive is
associated with each imbalance mass.
6. The machine according to claim 1, wherein a common drive is
associated with two imbalance masses.
7. The machine according to claim 5, wherein the respective drive
is designed as an electric drive.
8. The machine according to claim 7, wherein the electric drives
are controlled by means of a common control device.
9. The machine according to claim 5, wherein the respective drive
is designed as a hydraulic drive.
10. The machine according to claim 5, wherein an adjustment device
for a variable phase shift (.DELTA..PHI..sub.1, .DELTA..PHI..sub.2)
is associated with the respective drive.
11. The machine according to claim 1, wherein the vibration exciter
comprises at least four rotatable imbalance masses, of which two
imbalance masses in each case are driven right-turning and two
imbalance masses are driven left-turning.
12. The machine according to claim 11, wherein the two left-turning
imbalance masses are driven with a variably adjustable second phase
shift (.DELTA..PHI..sub.2) to one another, and wherein the two
right-turning imbalance masses are driven with a variably
adjustable second phase shift (.DELTA..PHI..sub.2) to one
another.
13. A method of operating a machine according to claim 1, wherein
the stabilizing unit is set down on the track via the vertical
drive and actuated with a vertical load, and wherein at least two
rotatable imbalance masses are driven applying a variably
adjustable second phase shift (.DELTA..PHI..sub.1,
.DELTA..PHI..sub.2) to one another.
14. The method according to claim 13, wherein one imbalance mass in
an imbalance pair is driven right-turning and one imbalance mass is
driven left-turning, and wherein at least one of these imbalance
masses is driven applying a first phase shift (.DELTA..PHI..sub.1)
which is variably adjustable with respect to an initial
position.
15. The method according to claim 13, wherein in the case of four
imbalance masses, two left-turning imbalance masses are driven
applying a variably adjustable second phase shift
(.DELTA..PHI..sub.2) to one another and two right-turning imbalance
masses are driven applying a variably adjustable second phase shift
(.DELTA..PHI..sub.2) to one another.
Description
FIELD OF TECHNOLOGY
[0001] The invention relates to a machine for stabilizing a track,
including a machine frame supported on on-track undercarriages and
a vertically adjustable stabilizing unit designed to roll on rails
of the track by means of unit rollers, the stabilizing unit
comprising a vibration exciter with rotating imbalance masses for
generating an impact force acting dynamically in a track plane
perpendicularly to a track longitudinal direction and a vertical
drive for generating a vertical load acting on the track. The
invention further relates to a method for operating such a
machine.
PRIOR ART
[0002] Machines for stabilizing a track are already well known from
the prior art. In a so-called dynamic track stabilizer, stabilizing
units located between two on-track undercarriages are lowered via a
vertical adjustment onto a track to be stabilized and are actuated
with a vertical load. During continuous forward travel, a
transverse vibration of the stabilizing units is transmitted to the
track via unit rollers and clamping rollers abutting outer sides of
the rail heads.
[0003] A machine of this type is known, for example, from WO
2008/009314 A1. In this, the stabilizing unit comprises adjustable
imbalance masses in order to quickly reduce the impact force, if
required, to a reduced value or to zero (for example, at bridges or
tunnels) and to raise it to the initial value immediately upon
reaching a track section to be stabilized.
[0004] A disadvantage here is the intricate structure of the moving
parts. In addition, a deliberate adjustment of the required impact
force is complicated as far as control engineering.
SUMMARY OF THE INVENTION
[0005] It is the object of the invention to provide an improvement
over the prior art for a machine of the kind mentioned at the
beginning. A further object lies in disclosing a method for
operating such a machine.
[0006] According to the invention, these objects are achieved by
way of a machine according to claim 1 and a method according to
claim 13. Dependent claims indicate advantageous embodiments of the
invention.
[0007] The invention provides that the vibration exciter comprises
at least two imbalance masses which are driven applying a variably
adjustable phase shift. By way of the variably adjustable phase
shift, the impact force acting on the track can be changed
purposefully. Depending on the arrangement of the imbalance masses,
an altered phase shift changes both the direction as well as the
power of the impact force.
[0008] Advantageously, a left-turning imbalance mass and a
right-turning imbalance mass form an imbalance mass pair, wherein
at least one imbalance mass of said imbalance mass pair is driven
applying a first phase shift which is variably adjustable with
respect to an initial position. The imbalance masses move against
one another, so that their centrifugal forces cancel each other out
in one direction and thus an undesired directional component of the
impact force is obliterated.
[0009] In an advantageous further development, an angle sensor is
associated with each imbalance mass. By means of the respective
angle sensor, the positions of the imbalance masses are always
known precisely. Thus it is possible to set a prescribed phase
shift by means of a control device. This is useful particularly in
the case of mechanical drives such as, for example, hydraulic
motors.
[0010] In addition, it is favourable if the respective imbalance
mass is arranged on the stabilizing unit with a rotation axis being
aligned in the track longitudinal direction. This alignment is
suitable especially for use in a stabilizing unit, since the
resulting impact force acts perpendicularly to the track
longitudinal direction on the track to be stabilized. In this
manner, energy is introduced into the track in an optimal way.
[0011] It is further advantageous if a separate drive is associated
with each imbalance mass. A separate drive for each imbalance mass
offers a structurally simple solution for being able to
purposefully control each imbalance mass with a separate rotation
angle position.
[0012] A simplified further development of the invention provides
that a common drive is associated in each case with two imbalance
masses. This solution is suited especially for compact stabilizing
units, wherein the phase shift is set by means of a variable
coupling, for example.
[0013] For the setting of the variable phase shift, it is
particularly favourable if the respective drive is designed as an
electric drive. Brushless electric motors or torque motors, for
example, are suited especially well here for control in an angle
control loop to achieve the desired phase shift.
[0014] In one embodiment of the invention, it is provided that the
electric drives are controlled by means of a common control device.
With this, the individual drives can be optimally coordinated with
one another and controlled precisely. During a working operation,
it is possible to access data previously stored in the control
device in order to adapt the electric drives and a phase shift in
an automatized way to local conditions and to an existing state of
the track.
[0015] In another embodiment of the invention, it may be
advantageous if the respective drive is designed as a hydraulic
drive. Thus, the drives can be integrated into an already existing
hydraulic system of the machine.
[0016] In an advantageous embodiment, an adjustment device for a
variable phase shift is associated with the respective drive. The
adjustment device is especially suited for mechanical drives to set
an exact phase shift. With this, the respective imbalance mass is
twisted at the required angle relative to the drive in a simple
manner. The adjustment device can be used for setting the phase
shift also when driving two imbalance masses with a common
drive.
[0017] A further improvement provides that the vibration exciter
comprises at least four rotatable imbalance masses, of which two
imbalance masses in each case are driven right-turning and two
imbalance masses are driven left-turning. By way of a purposeful
arrangement of at least four imbalance masses, a precise and quick
impact force adjustment up to a complete obliteration is
possible.
[0018] In addition, it is useful if the two left-turning imbalance
masses are driven with a variably adjustable second phase shift to
one another, and if the two right-turning imbalance masses are
driven with a variably adjustable second phase shift to one
another. In this way, the impact force resulting from all impact
masses can be adjusted relative to the track plane in an optimal
manner in order to adapt the stabilization of the track precisely
to local conditions.
[0019] The method, according to the invention, for operating a
machine provides that the stabilizing unit is set down on the track
via the vertical drive and actuated with a vertical load, and that
at least two rotatable imbalance masses are driven applying a
variably adjustable second phase shift to one another. Thus, a
track stabilization with a variable impact force is guaranteed
which is precisely adaptable to the local conditions.
[0020] In a favourable further development of the method, one
imbalance mass in an imbalance pair is driven left-turning and one
imbalance mass is driven right-turning, wherein at least one of
these imbalance masses is driven applying a first phase shift which
is variably adjustable with respect to an initial position. With
the direction of the impact force changing during this, it is
possible to boost the lowering of the track during the
stabilization, if required.
[0021] In another further development of the method, in the case of
four imbalance masses, two left-turning imbalance masses are driven
applying a variably adjustable second phase shift to one another
and two right-turning imbalance masses are driven applying a
variably adjustable second phase shift to one another. This ensures
a quick and exact impact force adjustment in the preferred
effective direction.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The invention will be described below by way of example with
reference to the accompanying drawings. There is shown in:
[0023] FIG. 1 a side view of a machine for stabilizing a track
[0024] FIG. 2 a detail view of a stabilizing unit
[0025] FIG. 3 a drive concept with two motors
[0026] FIG. 4 a drive concept with four motors
[0027] FIG. 5 an adjustment device for variable phase shift
[0028] FIG. 6 a vibration exciter with hollow shaft
[0029] FIG. 7 imbalance masses rotating in the same direction with
vibration obliteration
[0030] FIG. 8 imbalance masses rotating in the same direction with
reduced impact force
[0031] FIG. 9 imbalance masses rotating in the same direction with
maximal impact force
[0032] FIG. 10 imbalance masses rotating in opposite direction with
maximal impact force in one direction
[0033] FIG. 11 imbalance masses rotating in opposite direction with
reduced impact force
[0034] FIG. 12 four imbalance masses with complete obliteration of
the impact force
[0035] FIG. 13 four imbalance masses with maximal impact force in
x-direction
[0036] FIG. 14 four imbalance masses with complete obliteration of
the impact force
[0037] FIG. 15 four imbalance masses with maximal impact force in
y-direction
[0038] FIG. 16 four imbalance masses with different settings of the
phase shifts
DESCRIPTION OF THE EMBODIMENTS
[0039] FIG. 1 shows a machine 1 for stabilizing a track 3 resting
on ballast 2, the machine having a machine frame 6 supported via
on-track undercarriages 4 on rails 5. Arranged between the two
on-track undercarriages 4 positioned at the ends are two
stabilizing units 7, one following the other in the longitudinal
direction 8 of the track. These are each connected for vertical
adjustment to the machine frame 6 by vertical drives 9.
[0040] With the aid of unit rollers 10 designed to roll on the
rails 5, each stabilizing unit 7 can be brought into form-fitting
engagement with the track 3 in order to set the latter vibrating
with a desired vibration frequency. The unit rollers 10 comprise
two flanged rollers for each rail 5 which roll on the inside of the
rail 5, and a clamp roller which, during operation, is pressed
against the rail 5 from the outside by means of a clamp mechanism
33. A static vertical load is imparted to the track 3 by means of
the vertical drives 9.
[0041] The stabilizing units 7 are controlled by means of a common
control device 31. Drives 19 arranged in the stabilizing unit 7 are
connected to a common supply device 32. In the case of electric
drives 19, for example, this is a motor-generator unit with an
electric memory. Also, a catenary can be used for supplying
electric drives if the machine 1 has pantographs and appropriate
inverters. In the case of hydraulic drives 19, the supply device 32
is naturally integrated into a hydraulic system of the machine
1.
[0042] In FIG. 2, one of the two stabilizing units 7 is shown in
detail. Arranged inside an enclosure 11 is a vibration exciter 12
which comprises four rotation shafts 13 with imbalance masses 14
arranged thereon. Two rotation shafts 13 are arranged in each case
on two axes of rotation 15. An imbalance mass 14 is arranged on
each rotation shaft 13. Each rotation shaft 13 is mounted in the
enclosure 11 at either side of the imbalance mass 14 via roller
bearings 16.
[0043] Milled into an end, projecting from the enclosure 11, of the
respective rotation shaft 13 is a toothing 17 on which a rotor 18
of a drive 19, designed as a torque motor, is connected
form-fittingly to the associated rotation shaft 13. Arranged around
the rotor 18 of the respective torque motor is a stator 20 which is
connected by way of a motor housing 21 to the enclosure 11 of the
vibration exciter 12. Cooling fins 22 are arranged on the outside
of the motor housing 21. With this, heat arising during operation
can be reliably dissipated.
[0044] At a lower end, the stabilizing unit 7 is connected to a
stabilizing unit frame 23 in order to reliably transmit a vibration
to the unit-/clamp rollers 10 and thus to the track 3. The
imbalance masses 14 shown in FIG. 2 are driven independently of one
another, with freely definable phase shifts between the individual
imbalance masses 14. Use of four structurally identical drives 19,
rotation shafts 13 and imbalance masses 14 allows an easier
replaceability and supply of replacement parts in case of
maintenance or damage. For use in a machine 1 having two
stabilizing units 7, there is also an advantage resulting from the
structurally identical designs of both stabilizing units 7. In
addition, no transmission of force between the two stabilizing
units 7 is necessary.
[0045] FIG. 3 shows schematically a simplified variant of the
vibration exciter 12.
[0046] Both imbalance masses 14 are driven with a prescribed
rotation speed which defines the vibration frequency transmitted to
the track 3. In exceptional cases, it may be useful to drive both
imbalance masses 14 with different rotation speeds to cause a
continuous change of impact force. Otherwise, all imbalance masses
14 rotate with the same rotation speed. In this, an impact force
change is achieved solely by phase shifts .DELTA..PHI..sub.1,
.DELTA..PHI..sub.2, in which one imbalance mass 14 runs ahead of
the other one.
[0047] In order to be able to better explain the phase shifts
.DELTA..PHI..sub.1, .DELTA..PHI..sub.2, the four imbalance masses
14 are shown next to each other and denoted by the characters A, B,
C and D. Two imbalance masses A, B or C, D in each case form an
imbalance mass pair 34 which is driven by means of a common drive
19. In this, the rotation directions 30 of the two imbalance masses
A, B or C, D are opposite. In the example shown, the imbalance
masses A and C are driven left-turning, and the imbalance masses B
and D are driven right-turning. As shown in the embodiment
according to FIG. 2, two imbalance masses A, C or B, D in each case
can be arranged on a common rotation axis.
[0048] In order to achieve a change of rotation direction between
the imbalance masses A, B or C, D of an imbalance mass pair 34, a
reversing gear 24 is arranged in each case. In another variant, not
shown, the two imbalance masses A, C or B, D rotating in the same
direction are driven by means of a common drive 19. A reversing
gear 24 is then not required. An adjustment device 25 (FIG. 5) is
arranged for setting a phase shift between the imbalance masses 14
driven by means of a common drive 19. In this, a first phase shift
.DELTA..PHI..sub.1 with respect to an initial position can be set
at the imbalance masses 14 driven in opposite rotation directions.
A second phase shift .DELTA..PHI..sub.2 can be set at the imbalance
masses 14 rotating in the same direction.
[0049] In FIG. 4, taking reference to FIG. 2, the vibration exciter
12 is shown schematically, having a separate drive 19 per imbalance
mass 14. As in the example according to FIG. 3, the imbalance
masses A and C are driven left-turning and the imbalance masses B
and D are driven right-turning. For setting the phase shifts
.DELTA..PHI..sub.1, .DELTA..PHI..sub.2, each drive 19 can be
controlled in a rotation-angle-dependent way, or an adjustment
device 25 is arranged between each drive 19 and the associated
imbalance mass 14.
[0050] FIG. 5 shows, for example, a mechanical adjustment device 25
for twisting the rotation shaft 13 of the imbalance mass 14
relative to a drive shaft 26 of the drive 19. To that end, the
rotation shaft 13 is guided inside a sleeve 27 connected for
longitudinal displacement to the drive shaft 26. Like a spindle,
the rotation shaft 13 has at least one helical groove 28 with which
an inside counterpiece of the sleeve 27 is in engagement.
[0051] The sleeve 27 and the rotation shaft 13 are rotatably
mounted and connected to one another by means of a hydraulic
cylinder 29. If a longitudinal displacement of the sleeve 27
relative to the rotation shaft 13 is caused by means of the
hydraulic cylinder 29, the rotation shaft 13 including the
imbalance mass 14 twists at the desired angle with respect to drive
shaft 26. By twisting the rotation shaft 13 relative to the drive
shaft 26, a phase shift .DELTA..PHI..sub.1, .DELTA..PHI..sub.2 with
respect to another imbalance mass 14 is achieved.
[0052] The mechanical adjustment device 25 is suited especially in
combination with synchronously driven hydraulic motors. Here, an
angle sensor 35 is advantageously used to receive feedback about
the angular position of the respective drive shaft 26 or rotation
shaft 13. In a simplified solution as in FIG. 3, the arrangement of
an adjustment device 25 between the imbalance masses 14 provided
with a common drive 19 is also useful in order to achieve a phase
shift .DELTA..PHI..sub.1, .DELTA..PHI..sub.2 between the two
imbalance masses 14.
[0053] In the case of the vibration exciter 12 in FIG. 6, two
imbalance masses 14 rotate about a common rotation axis 15. In
this, one rotation shaft 13 is designed as a hollow shaft with an
outer imbalance mass 14. Inside the hollow shaft, a free end of the
other rotation shaft 13 is mounted with an inner imbalance mass 14.
The rotation shafts 13 are mounted in an enclosure 11 via further
roller bearings 16 and driven by means of separate drives 19. In
this, the centrifugal forces of the rotating imbalance masses 14
act in a common plane, so that no tilting moments occur which would
be possibly interfering. This mounting variant is particularly
suited for a vibration exciter 12 having only two imbalance masses
14.
[0054] In FIGS. 7 to 9, the effect of a variable second phase shift
42 by means of two imbalance masses 14 rotating in the same
direction is explained. At the left, the positions of the imbalance
masses 14 to one another are shown. In this, the axes of rotation
15 are oriented in the track longitudinal direction 8 and thus
extend parallel to a z-axis of a right-turning Cartesian coordinate
system x, y, z drawn in FIG. 1. Diagrams show directional
components F.sub.x, F.sub.y of a resulting impact force F.sub.S
over a common phase angle .PHI.. Shown below that are impact force
vectors for several phase angles .PHI. in the coordinate system x,
y, z moved along with the machine 1. If, in an initial position
according to FIG. 7, the second imbalance mass 14 is phase shifted
by 180.degree. relative to the first imbalance mass 14, the
centrifugal forces are obliterated. The resulting directional
components F.sub.y, F.sub.x of the impact force F.sub.s equal
zero.
[0055] In FIG. 8, a second phase shift .DELTA..PHI..sub.2 of
60.degree. in the rotation direction with respect to the initial
position is set for the second imbalance mass 14, so that the
second imbalance mass 14 runs ahead of the first imbalance mass 14
by a total of 240.degree.. From this, a rotating impact force
F.sub.S with constant value results. The maximal impact force
F.sub.s is attained if a second phase shift .DELTA..PHI..sub.2 of
180.degree. in the rotation direction with respect to the initial
position is set for the second imbalance mass 14. Then, both
imbalance masses 14 rotate synchronously, so that the centrifugal
forces add up (FIG. 9).
[0056] Corresponding images are shown in FIGS. 10 and 11 for two
imbalance masses 14 rotating in opposite directions. In an initial
position, the impact force component F.sub.y in y-direction is
obliterated, and the greatest impact force (F.sub.S) occurs in
x-direction (FIG. 10). A change of the impact force F.sub.S takes
place if a first phase shift .DELTA..PHI..sub.1 is set for an
imbalance mass 14 with respect to the initial position. In FIG. 11,
the first phase shift .DELTA..PHI..sub.1 of the second imbalance
mass 14 is 60.degree. in the rotation direction, for example. Then
the impact force F.sub.S diminishes. In this, the effective
direction of the impact force F.sub.S has an inclination angle with
respect to the x-axis which corresponds to half of the first phase
shift .DELTA..PHI..sub.1. Thus, a maximal impact force F.sub.S
parallel to the y-axis results in the case of a first phase shift
.DELTA..PHI..sub.1 of 180.degree..
[0057] In FIGS. 12 to 16, different phase shifts
.DELTA..PHI..sub.1, .DELTA..PHI..sub.2 of four imbalance masses A,
B, C and D according to FIGS. 3 and 4 are shown. Each of FIGS. 12
to 15 shows at the left side a first initial position of two
imbalance mass pairs 34 with imbalance masses A, B or C, D rotating
in opposite directions in each case (phase angle .PHI.=0). Shown
alongside (FIGS. 12, 13) or therebelow (FIGS. 14, 15) are
progressions of the impact forces F.sub.AB, F.sub.CD of the
imbalance mass pairs 34 and of the overall resulting impact force
F.sub.s over a common phase angle .PHI.. Further, the positions of
the imbalance masses 14 at a phase angle .PHI. of 90.degree.,
180.degree. and 270.degree. are shown.
[0058] With the aid of FIGS. 12 and 13, an impact force adjustment
in the direction of the x-axis, i.e. in the track plane
perpendicularly to the track longitudinal direction 8, is
explained. In this, the imbalance masses A, B or C, D of each
imbalance mass pair 34 are phase shifted by 180.degree. with regard
to one another. As a result of the rotation directions 30 opposing
one another, the centrifugal forces in the direction of the y-axis
are obliterated, and the y-component of the impact force F.sub.S
equals zero. In FIG. 12, the imbalance masses A, C or B, Direction,
which are driven in the same rotation direction, are additionally
phase shifted by 180.degree. with respect to one another. Thus, an
obliterated x-component also ensues for the overall resulting
impact force F.sub.S. Thus, in this initial position, no impact
force F.sub.S acts on the track 3 despite rotating imbalance masses
14.
[0059] For a maximal impact force F.sub.S in the x-direction, the
set second phase shift .DELTA..PHI..sub.2 is 180.degree. (FIG. 7).
Here, the imbalance masses A, C or B, D driven in the same rotation
direction run synchronously, so that the centrifugal forces in
x-direction add up. With the variably adjustable second phase shift
.DELTA..PHI..sub.2 in the range of 0.degree. to 180.degree., the
resulting impact force F.sub.S in the direction of the x-axis can
be precisely set from zero to the maximum.
[0060] The adjustment of the impact force F.sub.S in the direction
of the y-axis is explained with the aid of FIGS. 14 and 15. First,
in each imbalance mass pair 34 an imbalance mass B or D is phase
shifted with respect to the initial position in FIG. 12. In
particular, at both imbalance mass pairs 34 a first phase shift
.DELTA..PHI..sub.1 of 180.degree. is set, so that a complete
obliteration of the resulting impact force F.sub.S still exists
(FIG. 14). In order to achieve a maximal impact force F.sub.S in
the direction of the y-axis, a second phase shift of 180.degree. is
set relative to this new initial position (FIG. 15).
[0061] FIG. 16 shows five different impact force settings for four
imbalance masses A, B, C, D with the respectively resulting impact
force F.sub.S. From the left to the right, four positions of the
respective impact force setting are shown, i.e. at the phase angles
.PHI. being 0.degree., 90.degree., 180.degree. and 270.degree.. By
way of a changed specification of the first phase shift
.DELTA..PHI..sub.1 and the second phase shift .DELTA..PHI..sub.2 by
means of the common control device 31, the required impact force
F.sub.S is set quickly and precisely. In this, the control device
31 comprises a computing unit to set the optimal impact force
F.sub.S in dependence on a local track condition. For this
optimizing procedure, corresponding control signals from sensors
arranged on the machine 1 or track data determined beforehand are
supplied to the control device 31.
* * * * *